The goals of this project are to seek a better understanding of protein- membrane interactions by taking advantage of recently developed techniques, and to develop biosensors that employ the biorecognition capability of immobilized proteins. Three specific objectives will be achieved: (1) Study how redox proteins interact with biomembranes supported on electrodes and with their redox partner proteins embedded in the membranes using atomic force microscopy, surface plasmon resonance spectroscopy, and surface resistivity measurements. This study is not only crucial for developing biosensors based on immobilized proteins, but also directly relevant to many other biomedical applications, such as immunoassays and biocompatible materials for medical implants. Because the system mimics the natural environment of the proteins, this study will also provide new insights into the biological functions of the proteins. (2). Develop an atomic force sensing method to probe electron transfer-induced changes in the conformation and conformational breathing of the redox proteins. In contrast to crystallography and spectroscopy methods that measure quantities averaged over a large number of molecules, the method allows one to follow a single protein which is particularly suitable for understanding the role of the local environment of the protein in the electron transfer process. (3). Develop a miniaturized biosensor that integrates surface plasmon resonance spectroscopy with surface resistivity and electrochemical techniques. The miniaturization is important for in vivo applications, such as implanted glucose biosensors, and the integration of several different techniques will improve the reliability, sensitivity and selectivity of the biosensors that rely on only one of the three techniques.